Numerical Cognition Laboratory, Department of Psychology and Brain & Mind Institute, Western University, London ON, Canada; Center for the Study of Learning, Department of Pediatrics, Georgetown University, Washington DC, USA.
Numerical Cognition Laboratory, Department of Psychology and Brain & Mind Institute, Western University, London ON, Canada; Mathematical Brain Laboratory & Child Development and Social Policy Laboratory, Department of Psychology, Georgetown University, Washington DC, USA.
Cortex. 2019 May;114:41-53. doi: 10.1016/j.cortex.2018.11.027. Epub 2018 Dec 8.
Symbolic numbers have both cardinal (symbol-quantity) and ordinal (symbol-symbol) referents. Despite behavioural evidence suggesting distinct processing of cardinal and ordinal referents, little consensus has emerged from the neuroimaging literature on whether these processes have shared or distinct neural underpinnings. Moreover, it remains unclear how the neural correlates of cardinal and ordinal processing change with age. To address these unresolved questions, we investigated the neural correlates of cardinal (neural distance effect) and ordinal processing (neural reverse distance effect) in 50 children (ages 7-10) and 26 adults (ages 19-26). We found that adults recruited a largely left lateralized set of fronto-parietal regions for ordinal processing, whereas children showed activation in the right lateral orbital and inferior frontal gyri for both ordinal and cardinal processing. Additional analyses suggested that adults recruited the left intraparietal sulcus (IPS) more than children for ordinal processing, suggesting that the IPS may become increasingly tuned to ordinal symbolic properties over development. Together with previous literature documenting the importance of the left IPS for cardinal processing, our results suggest that cardinal and ordinal processing may share neural substrates in the left IPS and that this region may become specialized for both skills over development.
符号数字既有基数（符号-数量）又有序数（符号-符号）的指称。尽管行为证据表明基数和序数指称的处理方式不同，但神经影像学文献中对于这些过程是否具有共同或不同的神经基础仍未达成共识。此外，基数和序数处理的神经相关性如何随年龄变化尚不清楚。为了解决这些未解决的问题，我们在 50 名儿童（7-10 岁）和 26 名成年人（19-26 岁）中研究了基数（神经距离效应）和序数处理（神经反向距离效应）的神经相关性。我们发现，成年人在处理序数时主要利用左外侧的额顶叶区域，而儿童在处理序数和基数时都激活了右侧眶额和额下回。进一步的分析表明，成年人在处理序数时比儿童更多地利用左侧顶内沟（IPS），这表明 IPS 可能随着发育变得越来越适应序数符号属性。结合以前的文献记录了左侧 IPS 对基数处理的重要性，我们的结果表明，基数和序数处理可能在左侧 IPS 中共享神经基础，并且该区域可能随着发育而专门用于这两种技能。
